You will have heard a lot about the ‘hydrogen economy’ and how it is the future. You may also have heard that Scotland could be a world-leader on hydrogen. But what is the hydrogen economy, why is it important, is it over-hyped and what is happening in Scotland.
What is hydrogen?
Hydrogen is the simplest and most commonly occurring element in the universe, the first atoms to form and the basis of the first stars. It consists of one proton and one electron and on earth in its pure form it usually combines with a second hydrogen atom to exist as H2, the simplest molecule. It is the lightest element but is very reactive – it combines easily with other elements.
So why is it important?
When hydrogen burns it produces a lot of energy – in fact a given weight of hydrogen produces nearly three times as much energy as the same amount of petrol. But the enormous benefit of hydrogen is that when it burns it only produces energy and water and emits no greenhouse gases or other pollution. This gives it the potential to be an incredible powerful green fuel.
What would we use it for?
This is a complicated question because there are lots of possible uses but some are a much higher priority than others. So for example it is a VERY expensive way to heat a house but one of the very few replacements for aviation fuel and is an effective way to store power at the level of the electricity grid. There is sometimes too much hype about hydrogen solving everything but it really is one of the key components of a green future.
So why aren’t we using it?
If it’s so abundant, so clean and so powerful why aren’t we using it? The answer is that because it is so reactive it is rare to find it in the pure form we need for energy and when it does appear in its pure form it is so light it rises to the upper layer of the atmosphere. There is absolutely loads of hydrogen on earth, forming two out of three of the atoms in all the water on the planet. But getting the hydrogen out faces the reverse issue that burning it has – it takes a lot of energy to make it.
How do we make it?
This is where the story gets a bit more complicated – there are lots of ways to make hydrogen and few of them are genuinely clean. Indeed some of them are little better than using oil and gas. To make it more complicated, it has become the custom to describe all these different ways as a colour and this can make it even harder to follow.
What are the colours?
White – naturally-occurring hydrogen
Brown/black – made from the gasification of coal
Grey – made from reforming fossil gas
Blue – made from fossil gas or biomass but with the waste carbon dioxide captured and stored
Pink – made by running electricity from nuclear power through water, splitting it
Turquoise – made from methane but at very high temperatures to generate hydrogen and a solid carbon by-product
Yellow – splitting water using a mix of electricity supplies
Green – water is split using only renewable energy
But what is the reality?
White hydrogen is very rare, the technologies to make blue and turquoise hydrogen are not currently practical at scale, pink hydrogen has all the problems of nuclear power. This means that brown, black and grey hydrogen are by far the most common and green hydrogen only makes up 1% of the worlds hydrogen.
So hydrogen isn’t clean?
No, at the moment the vast majority of hydrogen is made from fossil fuels and produces the same amount of greenhouse gases as simply burning those fuels.
Why do we hear so much about blue hydrogen?
This is where we get to the situation in Scotland. The oil and gas industry are doing A LOT to promote blue hydrogen as clean hydrogen but there are major problems with this. First, even if you capture the greenhouse gases properly at least 30% and perhaps as much as 50% will escape or be too expensive to capture. But more to the point the technology for capturing and storing the carbon dioxide isn’t going to be ready in the next decade and few believe it ever will be.
So what is going on?
The oil and gas companies have two aims here. First of all they want to try and keep producing and using fossil fuels for as long as they can get away with but have to pretend that this can be ‘carbon neutral’ hence turning it into hydrogen and claiming to be able (eventually) to capture the carbon. The second reason is that by doing this they will own and be in control of the emerging hydrogen industry indefinitely. So first they want to delay the move to green hydrogen and then they want to make sure that only they are able to create the industry at scale.
What’s the alternative?
Scotland has so much spare renewable energy capacity that we could use that to create hydrogen from water without pollution. In particular Scotland’s enormous marine energy capacity isn’t being used yet and this could be used to make green hydrogen. Even more than that, this could form the basis of a National Energy Company, owning and developing this industry for the public good.